Here's a few for starters -
Grand Portage State Park - right along the Canadian border. Easy paved
path & steps to the largest waterfall in the state, but then hike to the middle falls. Very peaceful, and you probably won't run into anyone else.
Hike to the highest point in Minnesota at Eagle Mountain. It's a 20 mile drive in from Grand Marais, and you'll actually be hiking into the Boundary Waters area, but get a free day pass at the trailhead. Look for the plaque on the rock at the top.
Five miles up the shore from Tofte is the Oberg Loop hike. Seven scenic vistas at the top.
Just south of Tofte is Temperence River state park. Hike along the river towards Carlton Peak. It reminds me of the movie, the River Runs Through It - very scenic.
A few miles up the shore from Grand Marais is Devils Track Canyon, the deepest gourge in Minnesota. It's interesting, but not as deep as you're probably thinking, but a fun hike.